The present invention relates generally to so-called "electronic article surveillance", and in particular, to a system which involves the use of electronically detectable tags or labels which are attached to articles of merchandise in order to protect these articles from unauthorized removal, such as by shoplifting.
For enhanced security and inventory control, the use of electronic article surveillance (EAS) systems has become increasingly widespread. These systems utilize tags or labels which contain an electronic circuit (e.g., a resonant circuit) for interacting with an applied (e.g., swept radio-frequency) electromagnetic field. A transmitter and accompanying antenna produce this field, and a nearby receiver and accompanying antenna detect variations in the received field caused by the presence of a tag. This transmitting and receiving equipment is positioned at the location or locations where it is desired to detect the unauthorized removal of tag-bearing articles, e.g., at the exit of a retail store.
The tags attached to those articles whose removal is authorized (e.g., because these articles have been properly checked out) are either physically removed from the articles, or deactivated, i.e. treated so that they become incapable of producing detectable variations in the received field. Otherwise, these tags will be detected and an alarm signal will be produced by the equipment. Commercial EAS systems as generally described above are available from manufacturers such as Checkpoint Systems, Inc. of Thorofare, N.J., among others.
An important consideration in the use of such EAS systems is the manner in which the detectable tags or labels are applied to the articles which are to be protected. Some retail stores, for example, wish to have tags applied to all the articles in their inventory, while others wish to have tags applied only to some of these articles, leaving others untagged. Likewise the selection of the kinds of merchandise to be tagged may vary from store to store, and from time to time within the same store. Even within a common "family" of stores, such as the member stores of a chain, these practices may--and frequently do--vary from one store to another. This variety, coupled with the absence until now of any practical technique for avoiding local tag application, has led to the common practice for users of EAS systems to tag articles locally, at each EAS-equipped store.
However, such "store" tagging is time consuming and labor intensive. Also, store tagging is often delegated to personnel who may be limited in training or interest This can compromise the effectiveness of EAS, which is obviously significantly dependent upon proper tagging of the articles to be protected.
In view of all this, theoretical consideration has previously been given to the possibility of performing the desired tagging of articles at some other point, upstream from the store itself in the distribution chain, such as at the merchandise manufacturing stage, or at some intermediate stage of warehousing or distribution. This theoretical possibility has not found practical realization because of certain formidable obstacles.
If detectable tags were to be applied to articles of merchandise at their manufacturing stage, then a given product line would have to be processed in two different varieties, one tagged and one not tagged. Moreover, this segregation would have to be perpetuated throughout the subsequent distribution channels. The reason for this is that many--indeed most--stores do not yet use EAS. These non-EAS using stores would need to be reliably supplied with non-tagged articles; otherwise EAS tags would leave these stores, still attached to the articles being sold, and thereby create what is sometimes called "pollution" of the marketplace with EAS tags. Conversely, stores which do use EAS would have to be reliably supplied with tagged articles, or their EAS protection would become ineffective.
If, on the other hand, EAS tags were to be applied at an intermediate distribution stage, this would require breaking the bulk packaging which is typically used at those stages, handling the individual articles, and repackaging them in bulk. Furthermore, subsequent segregation of tagged and not-tagged articles would again be required.